WO2023032675A1

WO2023032675A1 - Polymer dispersion type liquid crystal film, and method for producing polymer dispersion type liquid crystal film

Info

Publication number: WO2023032675A1
Application number: PCT/JP2022/031088
Authority: WO
Inventors: 雅徳大塚; 真理子平井; 仁吉川
Original assignee: 日東電工株式会社
Priority date: 2021-09-01
Filing date: 2022-08-17
Publication date: 2023-03-09
Also published as: CN117897653A; TW202317378A; JP2023035529A

Abstract

The present invention provides a polymer dispersion type liquid crystal film capable of switching between a transparent state and a scattered state in only a prescribed region. The polymer dispersion type liquid crystal film according to the present invention comprises, in the following order: a first transparent conductive film (10); a polymer dispersion type liquid crystal layer (20) including a polymer matrix (22) and liquid crystal droplets (24) dispersed in the polymer matrix; and a second transparent conductive film (30). The polymer dispersion type liquid crystal layer comprises, in a plan view, a first region (A) and a second region (B) in which the amounts of change in haze caused by the application of a voltage differ, and, in the first region, the amount of change in haze caused by the application of a voltage is smaller than said amount of change in the second region. The liquid crystal droplets in the first region include a non-polymerizable liquid crystal compound (24a) and a liquid crystal polymer (24c).

Description

Polymer-dispersed liquid crystal film and method for producing polymer-dispersed liquid crystal film

The present invention relates to a polymer-dispersed liquid crystal film and a method for producing a polymer-dispersed liquid crystal film.

In recent years, light control films that exhibit different appearances depending on the state of voltage application have been applied to various applications such as advertisements, displays such as information boards, and smart windows.

A PDLC film having a polymer dispersed liquid crystal (hereinafter sometimes referred to as “PDLC”) layer between a pair of transparent electrode layers is a type of light control film, and can be applied in a voltage applied state or in a non-printed state. By switching between the additional states, it is possible to switch between a light scattering state (scattering state) and a light transmitting state (non-scattering state or transparent state). Specifically, the PDLC layer includes a polymer matrix and droplets of a liquid crystal compound dispersed in the polymer matrix (liquid crystal droplets), and the refractive index of the liquid crystal compound in the liquid crystal droplets and the polymer matrix is Liquid crystal droplets may become scattering particles due to differences and the like, causing light scattering.

Since the PDLC film generally exhibits a cloudy appearance in the scattering state, it can exhibit two appearances: cloudy (scattering state) and transparent (non-scattering state). A need exists for a light management film that can provide.

In relation to the above demand, Patent Document 1 discloses that a light control film capable of adjusting the total amount of incident light exhibits a transparent appearance in a non-scattering state by using a dichroic substance instead of a liquid crystal compound, Light management films have been proposed that exhibit a colored appearance in the scattering state.

Japanese Patent Application Laid-Open No. 2002-189123

In conventional light control films, switching between the transparent state and the scattering state was performed over the entire film surface, and it was not possible to perform the switching only in a predetermined area.

The present invention has been made to solve the above-mentioned conventional problems, and its main purpose is to provide a polymer-dispersed liquid crystal film capable of switching between a transparent state and a scattering state only in a predetermined region. be.

According to one aspect of the present invention, a first transparent conductive film, a polymer-dispersed liquid crystal layer including a polymer matrix and liquid crystal droplets dispersed in the polymer matrix, and a second transparent conductive film. and a polymer-dispersed liquid crystal film in this order, wherein the polymer-dispersed liquid crystal layer comprises a first region and a second region in which the amounts of change in haze due to voltage application are different in plan view. wherein the amount of change in haze due to voltage application in the first region is smaller than the amount of change in the second region, and the liquid crystal droplets in the first region are composed of a non-polymerizable liquid crystal compound and a liquid crystal polymer and a polymer dispersed liquid crystal film is provided.
In one embodiment, the liquid crystal droplets in the second region contain a non-polymerizable liquid crystal compound and a polymerizable liquid crystal compound.
In one embodiment, the content weight ratio of the non-polymerizable liquid crystal compound and the polymerizable liquid crystal compound in the second region (non-polymerizable liquid crystal compound:polymerizable liquid crystal compound) is 99:1 to 70:30. be.
In one embodiment, the liquid crystal polymer contained in the liquid crystal droplets in the first region is a polymerization product of the polymerizable liquid crystal compound contained in the liquid crystal droplets in the second region.
In one embodiment, the difference between the haze of the first region and the haze of the second region is increased by applying voltage.
In one embodiment, the liquid crystal polymer contained in the liquid crystal droplets in the first region is in a non-aligned state.
In one embodiment, the difference between the haze of the first region and the haze of the second region is reduced by applying a voltage.
In one embodiment, the liquid crystal polymer contained in the liquid crystal droplets in the first region is oriented in a predetermined direction.
According to another aspect of the present invention, a first transparent conductive film is coated with a coating liquid containing a polymer matrix-forming resin, a non-polymerizable liquid crystal compound, a polymerizable liquid crystal compound, and a solvent, Obtaining a coating layer, drying the coating layer to obtain a polymer dispersion type comprising a polymer matrix and liquid crystal droplets containing the non-polymerizable liquid crystal compound dispersed in the polymer matrix and the polymerizable liquid crystal compound obtaining a liquid crystal layer, laminating a second transparent conductive film on the polymer dispersed liquid crystal layer, and between the first transparent conductive film and the second transparent conductive film , the polymer-dispersed liquid crystal layer is irradiated with an active energy ray in a predetermined pattern while a voltage is applied to the polymer-dispersed liquid crystal layer so that the polymer-dispersed liquid crystal layer contains a liquid crystal polymer that is a polymerization product of the polymerizable liquid crystal compound and the non-polymerizable liquid crystal compound. A method of making a polymer dispersed liquid crystal film is provided, comprising forming a first region containing liquid crystal droplets.
According to another aspect of the present invention, a first transparent conductive film is coated with a coating liquid containing a polymer matrix-forming resin, a non-polymerizable liquid crystal compound, a polymerizable liquid crystal compound, and a solvent, Obtaining a coating layer, drying the coating layer to obtain a polymer dispersion type comprising a polymer matrix and liquid crystal droplets containing the non-polymerizable liquid crystal compound dispersed in the polymer matrix and the polymerizable liquid crystal compound obtaining a liquid crystal layer, laminating a second transparent conductive film on the polymer dispersed liquid crystal layer, and between the first transparent conductive film and the second transparent conductive film The polymer-dispersed liquid crystal layer is irradiated with an active energy ray in a predetermined pattern while no voltage is applied to the polymer-dispersed liquid crystal layer, so that the polymer-dispersed liquid crystal layer contains a liquid crystal polymer that is a polymerization product of the polymerizable liquid crystal compound and the non-polymerizable liquid crystal compound. A method of making a polymer dispersed liquid crystal film is provided, comprising forming a first region containing liquid crystal droplets.
In one embodiment, the coating liquid is an emulsion coating liquid in which liquid crystal particles containing the non-polymerizable liquid crystal compound and the polymerizable liquid crystal compound are dispersed in the solvent.
In one embodiment, the weight ratio of the total content of the non-polymerizable liquid crystal compound and the polymerizable liquid crystal compound in the coating liquid to the content of the polymer matrix-forming resin (liquid crystal compound:polymer matrix Forming resin) is 30:70 to 70:30.
In one embodiment, the content weight ratio of the non-polymerizable liquid crystal compound to the polymerizable liquid crystal compound (non-polymerizable liquid crystal compound:polymerizable liquid crystal compound) in the coating liquid is 99:1 to 70:30. be.

According to the embodiment of the present invention, since the orientation of the liquid crystal compound is restricted within the liquid crystal droplets in which the liquid crystal polymer exists, the change in haze caused by the change in voltage application state is suppressed. Therefore, by changing the voltage application state while the liquid crystal polymer is present in the liquid crystal droplets in the desired region, it is possible to suppress the haze change in that region while changing the haze in other regions. can. As a result, it is possible to provide a light control film that exhibits an appearance with a predetermined pattern when either voltage is applied or when no voltage is applied, and exhibits a highly uniform appearance in the other case.

(a) is a schematic plan view of an example of the PDLC film of the first embodiment of the present invention, and (b) is a schematic cross-sectional view for explaining the state of the PDLC film shown in (a) when no voltage is applied. and (c) is a schematic cross-sectional view for explaining the state of the PDLC film shown in (a) when a voltage is applied. (a) is a schematic plan view of an example of the PDLC film of the second embodiment of the present invention, and (b) is a schematic cross-sectional view for explaining the state of the PDLC film shown in (a) when no voltage is applied. and (c) is a schematic cross-sectional view for explaining the state of the PDLC film shown in (a) when a voltage is applied. 1 is a schematic diagram illustrating an example of a method for producing a PDLC film of the present invention; FIG. 1 is a schematic diagram illustrating an example of a method for producing a PDLC film of the present invention; FIG.

Preferred embodiments of the present invention will be described below, but the present invention is not limited to these embodiments. In this specification, "-" representing a numerical range includes its upper and lower limits.

A. Polymer Dispersed Liquid Crystal Film A polymer dispersed liquid crystal (PDLC) film according to an embodiment of the present invention includes a first transparent conductive film, a polymer matrix, and liquid crystal droplets dispersed in the polymer matrix. A PDLC layer and a second transparent conductive film are included in this order, and the PDLC layer has a first region and a second region having different amounts of change in haze due to voltage application in a plan view, and A change in haze due to voltage application in the first region is smaller than that in the second region, and the liquid crystal droplets in the first region contain a non-polymerizable liquid crystal compound and a liquid crystal polymer.

A-1. PDLC Film of First Embodiment FIG. 1(a) is a schematic plan view of an example of the PDLC film of the first embodiment of the present invention, and (b) is a voltage-free PDLC film shown in (a). FIG. 2C is a schematic cross-sectional view for explaining a state during heating, and (c) is a schematic cross-sectional view for explaining a state when voltage is applied to the PDLC film shown in (a). The PDLC film 100a includes a first transparent conductive film 10, a PDLC layer 20 including a polymer matrix 22 and liquid crystal droplets 24 dispersed in the polymer matrix 22, a second transparent conductive film 30, in that order. The PDLC layer 20 has a first region A and a second region B that have different amounts of change in haze due to voltage application in plan view. The liquid crystal droplets 24 in the first region A contain a non-polymerizable liquid crystal compound 24a and a liquid crystal polymer 24c, typically the liquid crystal polymer 24c exists in a non-aligned state. The liquid crystal droplets 24 in the second region B contain a non-polymerizable liquid crystal compound 24a and a polymerizable liquid crystal compound 24b. In the present specification, the expression that a certain compound is "in a non-oriented state" means that the compound is not arranged with a certain regularity.

As shown in FIG. 1B, in the PDLC film 100a when no voltage is applied, both the non-polymerizable liquid crystal compound 24a and the liquid crystal polymer 24c in the liquid crystal droplets 24 in the first region A are in a non-aligned state, Since both the non-polymerizable liquid crystal compound 24a and the polymerizable liquid crystal compound 24b in the liquid crystal droplets 24 in the second region B are in a non-aligned state, scattering of transmitted light occurs in both regions. Therefore, both the first region A and the second region B can be in the scattering state, and as a result, the entire main surface of the PDLC film 100a can be in the scattering state.

On the other hand, as shown in FIG. 1C, in the PDLC film 100a when a voltage is applied, both the non-polymerizable liquid crystal compound 24a and the polymerizable liquid crystal compound 24b in the liquid crystal droplets 24 in the second region B are transparent conductive. Since it is oriented in the direction perpendicular to the major surfaces of the

films

10 and 30 and scattering of transmitted light is suppressed, the haze of the region is reduced. On the other hand, in the first region A, the non-aligned liquid crystal polymer 24c prevents the alignment of the non-polymerizable liquid crystal compound 24a and maintains the non-aligned state, so that transmitted light is still scattered. Therefore, the amount of change in haze due to the application of voltage in the first region is smaller than the amount of change in the second region, and the difference between the haze in the first region and the haze in the second region increases with the application of voltage. do.

As described above, in the PDLC film 100a, when no voltage is applied, the entire main surface is in a scattering state and has a cloudy appearance. can appear opaque while the second region appears transparent. Therefore, the PDLC film 100a can exhibit different appearances by switching between voltage application and non-application.

The voltage applied to the PDLC film during voltage application is a voltage (operating voltage) capable of operating the PDLC film, and can be, for example, 5V to 200V, preferably 10V to 100V. As used herein, the term "haze when voltage is applied" means haze when an operating voltage is applied to the PDLC film, for example, haze when a voltage of 5 V or higher, 10 V or higher, or 20 V or higher is applied. could be.

The haze of the region corresponding to the first region of the PDLC film when no voltage is applied (hereinafter sometimes simply referred to as "haze of the first region") is, for example, 50% to 100%, preferably 70% to 100%. %. The haze of the first region when voltage is applied is, for example, 40% to 100%, preferably 60% to 100%. The amount of change in haze in the first region due to voltage application (|haze when no voltage is applied−haze when voltage is applied|) is, for example, 0% to 40%, preferably 0% to 30%.

The haze of the region corresponding to the second region of the PDLC film when no voltage is applied (hereinafter sometimes simply referred to as "the haze of the second region") is, for example, 50% to 100%, preferably 70% to 100%. %. The haze of the second region when voltage is applied is, for example, 1% to 20%, preferably 1% to 10%. The amount of change in haze in the second region due to voltage application (|haze when no voltage is applied−haze when voltage is applied|) is, for example, 30% to 99%, preferably 60% to 99%.

The amount of change in haze in the first region due to voltage application is smaller than the amount of change in haze in the second region due to voltage application, and the difference is, for example, 10% to 99%, preferably 30% to 99%. .

The total light transmittance of the region corresponding to the first region of the PDLC film when no voltage is applied (hereinafter sometimes simply referred to as the "total light transmittance of the first region") is, for example, 50% to 95%, Preferably it is 60% to 90%. The total light transmittance of the first region when voltage is applied is, for example, 50% to 95%, preferably 60% to 90%. Total light transmittance can be measured according to JIS K 7361.

The total light transmittance of the region corresponding to the second region of the PDLC film when no voltage is applied (hereinafter sometimes simply referred to as "the total light transmittance of the second region") is, for example, 50% to 95%, Preferably it is 60% to 90%. The total light transmittance of the second region when voltage is applied is, for example, 70% to 95%, preferably 80% to 90%.

The thickness of the PDLC film is, for example, 30 μm to 250 μm, preferably 50 μm to 150 μm.

A-1-1. First Transparent Conductive Film The first transparent conductive film 10 typically has a first transparent substrate 12 and a first transparent electrode layer 14 provided on one side thereof. The first transparent conductive film 10 may have a hard coat layer on one side or both sides of the first transparent substrate 12, if necessary. A refractive index adjusting layer may be provided between the transparent electrode layer 14 of .

The surface resistance value of the first transparent conductive film is preferably 1 Ω/□ to 1000 Ω/□, more preferably 5 Ω/□ to 300 Ω/□, even more preferably 10 Ω/□ to 200 Ω/□. .

The haze value of the first transparent conductive film is preferably 20% or less, more preferably 10% or less, still more preferably 0.1% to 10%.

The total light transmittance of the first transparent conductive film is preferably 30% or higher, more preferably 60% or higher, and even more preferably 80% or higher.

The first transparent base material can be formed using any appropriate material. Specifically, for example, polymer substrates such as films and plastic substrates are preferably used. This is because it is excellent in smoothness and wettability with the composition for forming a transparent electrode layer, and productivity can be greatly improved by continuous production using rolls.

The material that constitutes the first transparent substrate is typically a polymer film containing a thermoplastic resin as a main component. Examples of thermoplastic resins include polyester-based resins; cycloolefin-based resins such as polynorbornene; acrylic-based resins; polycarbonate resins; and cellulose-based resins. Among them, polyester resins, cycloolefin resins and acrylic resins are preferable. These resins are excellent in transparency, mechanical strength, thermal stability, moisture barrier properties, and the like. You may use the said thermoplastic resin individually or in combination of 2 or more types. Further, an optical film used for a polarizing plate, such as a low retardation substrate, a high retardation substrate, a retardation plate, an absorptive polarizing film, a polarized selective reflection film, etc., can also be used as the first transparent substrate. is.

The thickness of the first transparent substrate is preferably 200 μm or less, more preferably 3 μm to 100 μm, still more preferably 5 μm to 70 μm. By setting the thickness of the first transparent base material to 200 μm or less, the function of the PDLC layer can be sufficiently exhibited.

The total light transmittance of the first transparent substrate is preferably 30% or higher, more preferably 60% or higher, and even more preferably 80% or higher.

The first transparent electrode layer can be formed using, for example, metal oxides such as indium tin oxide (ITO), zinc oxide (ZnO), tin oxide (SnO ₂ ). A transparent electrode layer, preferably comprising ITO, is formed. A transparent electrode layer containing ITO is excellent in transparency. The first transparent electrode layer can be patterned into a desired shape depending on the purpose.

The light transmittance of the first transparent electrode layer is preferably 85% or higher, more preferably 87% or higher, and still more preferably 90% or higher. By using a transparent electrode layer having a light transmittance in such a range, a high light transmittance is obtained in a transparent state. The higher the light transmittance, the better, but the upper limit is, for example, 99%.

Preferably, the first transparent electrode layer contains crystal grains. Light transmittance can be improved by containing crystal grains. Although the method for forming the crystal grains is not limited, the crystal grains can be preferably formed by, for example, heating in the atmosphere. The area occupation ratio of crystal grains in the transparent electrode layer is, for example, 30% or more, preferably 50% or more, and more preferably 80% or more. The upper limit of the area occupation ratio is, for example, 100%. If the area occupation ratio of the crystal grains is within the above range, the light transmittance can be improved. The area occupation ratio of the crystal grains can be calculated from the area ratio of the crystal grain region and the amorphous region by observing the surface of the transparent electrode layer with a transmission electron microscope (TEM).

The surface roughness Ra of the first transparent electrode layer is, for example, 0.1 nm or more. If the surface roughness Ra of the first transparent electrode layer is less than 0.1 nm, the adhesion to the substrate may deteriorate. The upper limit of the surface roughness Ra of the first transparent electrode layer is preferably less than 1.2 nm, more preferably 1.0 nm or less, even more preferably less than 1.0 nm, particularly preferably 0.8 nm. It is below. If the surface roughness Ra of the first transparent electrode layer is too large, it may become difficult to suitably form crystal grains. The surface roughness Ra in this specification means the arithmetic mean roughness Ra measured by AFM (Atomic Force Microscope).

The thickness of the first transparent electrode layer is, for example, 10 nm or more, preferably 15 nm or more. If the thickness of the transparent electrode layer is less than 10 nm, the area occupation ratio of crystal grains may decrease. The upper limit of the thickness of the first transparent electrode layer is, for example, 50 nm or less, preferably 35 nm or less, more preferably less than 30 nm, still more preferably 27 nm or less. If the thickness of the transparent electrode layer exceeds 50 nm, the transmittance may deteriorate, and the surface roughness of the transparent electrode layer may increase.

The first transparent electrode layer is provided on one surface of the first transparent substrate by, for example, sputtering. After the metal oxide layer is formed by sputtering, it can be crystallized by annealing. Annealing is performed, for example, by heat treatment at 120° C. to 300° C. for 10 minutes to 120 minutes.

The refractive index adjusting layer can control the hue and/or transmittance of the PDLC film. The refractive index adjusting layer may consist of a single layer, or may be a laminate of two or more layers.

The refractive index of the refractive index adjusting layer is preferably 1.3 to 1.8, more preferably 1.35 to 1.7, even more preferably 1.38 to 1.68. In the case of a single layer, for example, when the transparent electrode layer is ITO, a rather low refractive index is desirable, for example, 1.38 to 1.46, so as to optically relax the refractive index of ITO. As a result, interfacial reflection between the transparent base material and the transparent electrode layer can be preferably reduced.

The refractive index adjusting layer is made of an inorganic substance, an organic substance, or a mixture of an inorganic substance and an organic substance. Materials for forming the refractive index adjustment layer include NaF, _Na3AlF6 , LiF, _MgF2 , _CaF2, _SiO2 , _LaF3 , _CeF3 _, _Al2O3 _, _TiO2 _, _Ta2O5 , and _ZrO2. , ZnO, ZnS, and SiO _x (where x is 1.5 or more and less than 2), and organic substances such as acrylic resins, epoxy resins, urethane resins, melamine resins, alkyd resins, and siloxane-based polymers. In particular, it is preferable to use a thermosetting resin composed of a mixture of melamine resin, alkyd resin and organic silane condensate as the organic material.

The refractive index adjusting layer may contain nanoparticles with an average particle size of 1 nm to 100 nm. By containing nanoparticles in the refractive index adjusting layer, the refractive index of the refractive index adjusting layer itself can be easily adjusted.

The content of nanoparticles in the refractive index adjusting layer is preferably 0.1% by weight to 90% by weight. Moreover, the content of the nanoparticles in the refractive index adjusting layer is more preferably 10 wt % to 80 wt %, and even more preferably 20 wt % to 70 wt %.

Examples of inorganic oxides that form nanoparticles include silicon oxide (silica), hollow nanosilica, titanium oxide, aluminum oxide, zinc oxide, tin oxide, zirconium oxide, and niobium oxide. Among these, silicon oxide (silica), titanium oxide, aluminum oxide, zinc oxide, tin oxide, zirconium oxide, and niobium oxide are preferred. These may be used individually by 1 type, and may use 2 or more types together.

The thickness of the refractive index adjusting layer is preferably 10 nm to 200 nm, more preferably 20 nm to 150 nm, and even more preferably 30 nm to 130 nm. If the thickness of the refractive index adjusting layer is too small, it is difficult to form a continuous film. Further, when the thickness of the refractive index adjusting layer is excessively large, there is a tendency that the transparency in the transparent state is lowered and cracks are likely to occur.

The refractive index adjustment layer can be formed using the above materials by a coating method such as a wet method, a gravure coating method or a bar coating method, a vacuum deposition method, a sputtering method, an ion plating method, or the like.

A-1-2. PDLC Layer The PDLC layer 20 includes a polymer matrix 22 and liquid crystal compound droplets (liquid crystal droplets) 24 dispersed in the polymer matrix 22 . As shown in FIG. 1, the PDLC layer 20 has a first region A and a second region B, and the liquid crystal droplets 24 in the first region A are composed of a non-polymerizable liquid crystal compound 24a and a liquid crystal polymer in a non-aligned state. 24c, and the liquid crystal droplet 24 in the second region B includes a non-polymerizable liquid crystal compound 24a and a polymerizable liquid crystal compound 24b. The first region A and the second region B can be formed in any suitable pattern according to the design desired for the PDLC film.

The polymer matrix can be composed of any suitable resin. The polymer matrix-forming resin can be appropriately selected according to the light transmittance, the refractive index of the liquid crystal compound, the adhesion to the transparent conductive film, and the like. For example, water-soluble resins or water-dispersible resins such as urethane-based resins, polyvinyl alcohol-based resins, polyethylene-based resins, polypropylene-based resins, and acrylic-based resins can be preferably used. The polymer matrix-forming resin may be used alone or in combination.

The content of the polymer matrix in the PDLC layer is, for example, 30% to 70% by weight, preferably 35% to 65% by weight, more preferably 40% to 60% by weight, in both the first region and the second region. % by weight. If the content of the polymer matrix is within this range, a good dimming function can be exhibited at a moderate operating voltage, good mechanical strength can be obtained, liquid crystal leakage from the edges can be prevented, etc. effect can be obtained.

Any appropriate liquid crystal compound can be used as the non-polymerizable liquid crystal compound. Preferably, the birefringence Δn of 0.05 to 0.50 at a wavelength of 589 nm (= ne-no; ne is the refractive index in the long axis direction of the liquid crystal compound molecule, no is the refractive index in the short axis direction of the liquid crystal compound molecule), and more A liquid crystal compound having a birefringence Δn of 0.10 to 0.45 is preferably used.

The dielectric anisotropy of the non-polymerizable liquid crystal compound may be positive or negative. Non-polymerizable liquid crystal compounds can be, for example, nematic, smectic, or cholesteric liquid crystal compounds. It is preferable to use a nematic type liquid crystal compound because excellent transparency can be achieved in the transparent state.

Nematic type liquid crystal compounds include biphenyl-based compounds, phenylbenzoate-based compounds, cyclohexylbenzene-based compounds, azoxybenzene-based compounds, azobenzene-based compounds, azomethine-based compounds, terphenyl-based compounds, biphenylbenzoate-based compounds, cyclohexylbiphenyl-based compounds, Examples include phenylpyridine-based compounds, cyclohexylpyrimidine-based compounds, cholesterol-based compounds, and fluorine-based compounds. These low-molecular-weight liquid crystal compounds may be used alone or in combination.

The polymerizable liquid crystal compound can be appropriately selected according to the light transmittance, compatibility with the non-polymerizable liquid crystal compound, and the like. The polymerizable liquid crystal compound may be of a bifunctional or higher crosslinked type. Polymerizable liquid crystal compounds include, for example, polymeric mesogenic compounds described in JP-T-2002-533742 (WO00/37585), EP358208 (US5211877), EP66137 (US4388453), WO93/22397, EP0261712, DE19504224, DE4408171, and GB2280445. etc. can be used. A specific example of such a polymerizable mesogenic compound is LC242 (trade name) available from BASF. As the polymerizable liquid crystal compound, for example, a nematic liquid crystal monomer is preferable.

A liquid crystal polymer is typically a polymerization product of the polymerizable liquid crystal compound. A polymer may be formed by polymerization of the polymerizable liquid crystal compound, and a network structure may be formed by cross-linking, but these are non-liquid crystalline. Therefore, in a liquid crystal polymer, for example, a transition to a liquid crystal phase, a glass phase, or a crystal phase due to a temperature change peculiar to a liquid crystalline compound does not occur.

A liquid crystal polymer typically exists in a non-aligned state in a liquid crystal droplet. Since the liquid crystal polymer in the liquid crystal droplets is in a non-aligned state, the first region maintains a high haze (for example, 40% to 100%, preferably 60% to 100%) even when a voltage is applied. obtain.

The total content of the non-polymerizable liquid crystal compound and the liquid crystal polymer in the first region is, for example, 30 wt% to 70 wt%, preferably 35 wt% to 65 wt%, more preferably 40 wt% to 60 wt%. . The weight content ratio of the non-polymerizable liquid crystal compound to the liquid crystal polymer (non-polymerizable liquid crystal compound: liquid crystal polymer) in the first region is, for example, 99:1 to 70:30, preferably 95:5 to 80:20. be. Further, the total content of the polymer matrix, the non-polymerizable liquid crystal compound and the liquid crystal polymer in the first region may be, for example, 90% to 99.9% by weight, preferably 95% to 99.9% by weight. .

The total content of the non-polymerizable liquid crystal compound and the polymerizable liquid crystal compound in the second region is, for example, 30% to 70% by weight, preferably 35% to 65% by weight, more preferably 40% to 60% by weight. is. Further, the weight content ratio of the non-polymerizable liquid crystal compound and the polymerizable liquid crystal compound (non-polymerizable liquid crystal compound:polymerizable liquid crystal compound) in the second region is, for example, 99:1 to 70:30, preferably 95:5 to It is 80:20. In addition, the total content of the polymer matrix, the non-polymerizable liquid crystal compound and the polymerizable liquid crystal compound in the second region is, for example, 90% by weight to 99.9% by weight, preferably 95% by weight to 99.9% by weight. could be.

As detailed in section B, the PDLC layer having the first region and the second region is polymerized in a predetermined region of the PDLC layer containing liquid crystal droplets containing a non-polymerizable liquid crystal compound and a polymerizable liquid crystal compound. It may be formed by polymerizing a liquid crystalline compound to form a liquid crystalline polymer, in which case the predetermined area becomes the first area and the other area becomes the second area. Therefore, in the first region and the second region, the liquid crystal droplet may further contain a polymerization initiator. The content of the polymerization initiator is as described in Section B. In addition, unreacted polymerizable liquid crystal compounds may remain in the liquid crystal droplets in the first region. The content of the unreacted polymerizable liquid crystal compound in the first region is, for example, 3% by weight or less, preferably 1% by weight or less. Further, it is preferable that substantially no liquid crystal polymer is present in the liquid crystal droplets in the second region. The content of the liquid crystal polymer in the second region is, for example, 3% by weight or less, preferably 1% by weight or less.

The average particle size of liquid crystal droplets can be, for example, 0.3 μm to 9 μm, preferably 0.4 μm to 8 μm. If the average particle size of the liquid crystal droplets is too small, the liquid crystal droplet size is smaller than the wavelength of the light, so the light passes through the liquid crystal droplets without being scattered, and as a result, sufficient haze cannot be obtained. There can be a problem that there is no On the other hand, if the average particle size is too large, the size of the liquid crystal droplets is too large for the wavelength of light, which may cause a problem that a sufficient haze cannot be obtained. The average particle size of the liquid crystal droplets in the PDLC layer is the volume average particle size of the liquid crystal droplets when viewed from a direction perpendicular to the main surface of the PDLC film.

The thickness of the PDLC layer is typically 2 μm to 40 μm, preferably 3 μm to 35 μm, more preferably 4 μm to 30 μm.

A-1-3. Second Transparent Conductive Film The second transparent conductive film 30 typically has a second transparent substrate 32 and a second transparent electrode layer 34 provided on one side thereof. The second transparent conductive film 30 may have a hard coat layer on one side or both sides of the second transparent substrate 32, if necessary. A refractive index adjusting layer may be provided between the transparent electrode layer 34 of .

The surface resistance value of the second transparent conductive film is preferably 1 Ω/□ to 1000 Ω/□, more preferably 5 Ω/□ to 300 Ω/□, even more preferably 10 Ω/□ to 200 Ω/□. .

The haze value of the second transparent conductive film is preferably 20% or less, more preferably 10% or less, still more preferably 0.1% to 10%.

The total light transmittance of the second transparent conductive film is preferably 30% or higher, more preferably 60% or higher, and even more preferably 80% or higher.

For the second transparent base material and the second transparent electrode layer, the same explanation as for the first transparent base material and the first transparent electrode layer can be applied. The second transparent conductive film may have the same configuration as the first transparent conductive film, or may have a different configuration.

A-2. PDLC Film of Second Embodiment FIG. 2(a) is a schematic plan view of an example of the PDLC film of the second embodiment of the present invention, and (b) is a voltage-free PDLC film shown in (a). FIG. 2C is a schematic cross-sectional view for explaining a state during heating, and (c) is a schematic cross-sectional view for explaining a state when voltage is applied to the PDLC film shown in (a). The PDLC film 100b includes a first transparent conductive film 10, a PDLC layer 20 including a polymer matrix 22 and liquid crystal droplets 24 dispersed in the polymer matrix 22, a second transparent conductive film 30, in that order. The PDLC layer 20 has a first region A and a second region B that have different amounts of change in haze due to voltage application in plan view. The liquid crystal droplets 24 in the first region A contain a non-polymerizable liquid crystal compound 24a and a liquid crystal polymer 24c. perpendicular to the main surface). The liquid crystal droplets 24 in the second region B contain a non-polymerizable liquid crystal compound 24a and a polymerizable liquid crystal compound 24b.

As shown in FIG. 2B, in the PDLC film 100b when no voltage is applied, both the non-polymerizable liquid crystal compound 24a and the polymerizable liquid crystal compound 24b in the liquid crystal droplets 24 in the second region B are in a non-aligned state. Something causes scattering of the transmitted light. On the other hand, in the first region A, the non-polymerizable liquid crystal compound 24a is oriented along the orientation direction of the liquid crystal polymer 24c, so that scattering of transmitted light is suppressed. Therefore, in the PDLC film 100b, the first region A can be in a transparent state and the second region B can be in a scattering state.

On the other hand, as shown in FIG. 2C, in the PDLC film 100b when a voltage is applied, both the non-polymerizable liquid crystal compound 24a and the polymerizable liquid crystal compound 24b in the liquid crystal droplets 24 in the second region B are transparent conductive. It is oriented in the direction perpendicular to the major surfaces of the

films

10 and 30, and as a result of suppressing the scattering of transmitted light, the haze is reduced. On the other hand, in the first region A, since the orientation of the non-polymerizable liquid crystal compound 24a does not change significantly, scattering of transmitted light is still suppressed. Therefore, the amount of change in haze due to the application of voltage in the first region is smaller than the amount of change in the second region, and the difference between the haze in the first region and the haze in the second region is reduced by the application of voltage. do.

As described above, in the PDLC film 100b, when no voltage is applied, the first region is transparent, and the second region has a cloudy appearance. state, resulting in a transparent appearance over the entire major surface. Therefore, the PDLC film 100b can exhibit different appearances by switching between voltage application and non-application.

The voltage applied to the PDLC film during voltage application is a voltage (operating voltage) capable of operating the PDLC film, and can be, for example, 5V to 200V, preferably 10V to 100V.

The haze of the first region when no voltage is applied is, for example, 1% to 20%, preferably 1% to 10%. The haze of the first region when voltage is applied is, for example, 1% to 20%, preferably 1% to 10%. The amount of change in haze in the first region due to voltage application (|haze when no voltage is applied−haze when voltage is applied|) is, for example, 0% to 20%, preferably 0% to 10%.

The haze of the second region when no voltage is applied is, for example, 50% to 100%, preferably 70% to 100%. The haze of the second region when voltage is applied is, for example, 1% to 20%, preferably 1% to 10%. The amount of change in haze in the second region due to voltage application (|haze when no voltage is applied−haze when voltage is applied|) is, for example, 30% to 99%, preferably 60% to 99%.

The total light transmittance of the first region when no voltage is applied is, for example, 70% to 95%, preferably 80% to 90%. The total light transmittance of the first region when voltage is applied is, for example, 70% to 95%, preferably 80% to 90%.

The total light transmittance of the second region when no voltage is applied is, for example, 50% to 95%, preferably 60% to 90%. The total light transmittance of the second region when voltage is applied is, for example, 70% to 95%, preferably 80% to 90%.

Regarding the PDLC film of the second embodiment, the first transparent conductive film and the second transparent conductive film are the first transparent conductive film and the second transparent conductive film in the PDLC film of the first embodiment. The same explanations as for the sex films can be applied respectively. Also, with respect to the PDLC layer, the same description as that for the PDLC layer in the PDLC film of the first embodiment applies, except that the liquid crystal polymer contained in the liquid crystal droplets in the first region is oriented in a predetermined direction. be able to.

In the first region of the PDLC layer, the liquid crystal polymer contained in the liquid crystal droplets is oriented in a predetermined direction. The liquid crystal polymer preferably forms an angle substantially perpendicular to the major surfaces of the first transparent conductive film and the second transparent conductive film, for example, 90°±5°, preferably 90°±3°. are oriented as Since the liquid crystal polymer in the liquid crystal droplets is oriented in a predetermined direction, the first region has a low haze (for example, 1% to 20%, preferably 1% to 10%) even when no voltage is applied. ) can be maintained.

B. Method for Producing Polymer Dispersed Liquid Crystal Film According to one aspect of the present invention, a method for producing a polymer dispersed liquid crystal (PDLC) film is provided. A method for manufacturing a PDLC film according to an embodiment of the present invention comprises:
(Step A) coating a first transparent conductive film with a coating liquid containing a polymer matrix-forming resin, a non-polymerizable liquid crystal compound, a polymerizable liquid crystal compound, and a solvent to obtain a coating layer;
(Step B) drying the coating layer to obtain a PDLC layer containing a polymer matrix and liquid crystal droplets containing the non-polymerizable liquid crystal compound dispersed in the polymer matrix and the polymerizable liquid crystal compound;
(Step C) laminating a second transparent conductive film on the PDLC layer, and (Step D) irradiating the PDLC layer with an active energy ray in a predetermined pattern to polymerize the polymerizable liquid crystal compound. forming a first region containing liquid crystal droplets containing the product liquid crystal polymer and the non-polymerizable liquid crystal compound;
including. According to the method for manufacturing a PDLC film according to an embodiment of the present invention, the liquid crystal droplets include the first region containing the non-polymerizable liquid crystal compound and the liquid crystal polymer, and the liquid crystal droplets contain the non-polymerizable liquid crystal compound and the polymerizable liquid crystal compound. A PDLC layer having a second region containing

In one embodiment, the active energy ray irradiation in step D is performed with no voltage applied between the first transparent conductive film and the second transparent conductive film. In another embodiment, the active energy ray irradiation in step D is performed with a voltage applied between the first transparent conductive film and the second transparent conductive film.

B-1. Process A
In step A, a coating liquid containing a polymer matrix-forming resin, a non-polymerizable liquid crystal compound, a polymerizable liquid crystal compound, and a solvent is applied to the first transparent conductive film to obtain a coating layer.

The coating liquid is preferably an emulsion in which liquid crystal particles containing a non-polymerizable liquid crystal compound and a polymerizable liquid crystal compound are dispersed in a solvent (hereinafter sometimes referred to as "emulsion coating liquid"). In one embodiment, the coating liquid is an emulsion coating liquid in which polymer matrix-forming resin particles and liquid crystal particles containing a non-polymerizable liquid crystal compound and a polymerizable liquid crystal compound are dispersed in a solvent. The emulsion coating liquid preferably further contains a polymerization initiator in the liquid crystal particles, and may further contain any suitable additive depending on the purpose.

As the solvent, water or a mixed solvent of water and a water-miscible organic solvent can be preferably used. Water-miscible organic solvents include C1-3 alcohols, acetone, DMSO and the like. The non-polymerizable liquid crystal compound, the polymerizable liquid crystal compound and the polymer matrix-forming resin are as described in Section A-1-2. Optional additives include dispersants, leveling agents, cross-linking agents, and the like.

The content ratio of the liquid crystal compound in the solid content of the coating liquid (the total content ratio of the non-polymerizable liquid crystal compound and the polymerizable liquid crystal compound) is, for example, 30% to 70% by weight, preferably 35% to 65% by weight, More preferably, it may be 40% to 60% by weight.

The content weight ratio of the non-polymerizable liquid crystal compound and the polymerizable liquid crystal compound (non-polymerizable liquid crystal compound:polymerizable liquid crystal compound) in the coating liquid is preferably from 99:1 to 70:30, more preferably from 95:5 to It can be 80:20.

The content of the polymer matrix-forming resin in the solid content of the coating solution can be, for example, 30% to 70% by weight, preferably 35% to 65% by weight, and more preferably 40% to 60% by weight. .

The weight ratio of the content of the liquid crystal compound in the coating liquid (the total content of the non-polymerizable liquid crystal compound and the polymerizable liquid crystal compound) to the content of the polymer matrix-forming resin (liquid crystal compound: polymer matrix-forming resin ) can be, for example, 30:70 to 70:30, preferably 35:65 to 65:35, more preferably 40:60 to 60:40. Further, the total content ratio of the polymer matrix-forming resin, the non-polymerizable liquid crystal compound and the polymerizable liquid crystal compound in the solid content of the coating liquid is, for example, 90% by weight to 99.9% by weight, preferably 95% by weight to 99.9% by weight.

The average particle size of the liquid crystal particles is preferably 0.3 μm or more, more preferably 0.4 μm or more. Also, the average particle size of the liquid crystal particles is preferably 9 μm or less, more preferably 8 μm or less. If the average particle size of the liquid crystal particles is within this range, the average particle size of the liquid crystal droplets in the PDLC layer can be within the desired range. The average particle size of the liquid crystal particles is the volume average particle size.

The average particle size of the liquid crystal particles preferably has a relatively narrow particle size distribution. The coefficient of variation (CV value) of the average particle diameter of the liquid crystal particles may be, for example, less than 0.40, preferably 0.35 or less, more preferably 0.30 or less. In one embodiment, an emulsion coating solution that does not substantially contain liquid crystal particles having a particle size of less than 0.3 μm or more than 9 μm (for example, a liquid crystal particle having a particle size of less than 0.3 μm or more than 9 μm with respect to the total volume of liquid crystal particles). An emulsion coating liquid in which the volume ratio of certain liquid crystal particles is 10% or less can be used.

The average particle size of the polymer matrix-forming resin particles is preferably 10 nm to 500 nm, more preferably 30 nm to 300 nm, still more preferably 50 nm to 200 nm. Two or more kinds of resin particles having different resin types and/or different average particle sizes may be used. The average particle size of the polymer matrix-forming resin particles means a volume-average median size, and can be measured using a dynamic light scattering particle size distribution analyzer.

Any appropriate photopolymerization initiator can be used as the polymerization initiator depending on the purpose and desired properties. Specific examples of photopolymerization initiators include 2,2-dimethoxy-2-phenylacetophenone, acetophenone, benzophenone, xanthone, 3-methylacetophenone, 4-chlorobenzophenone, 4,4′-dimethoxybenzophenone, benzoinpropyl ether, benzyl dimethyl ketal, N,N,N',N'-tetramethyl-4,4'-diaminobenzophenone, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 2,4, 6-trimethylbenzoyldiphenylphosphine oxide, bis-(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-2,4-dipentoxyphenylphosphine oxide, Bis(2,6-dimethoxy-benzoyl)-(2,4,4-trimethyl-pentyl)-phosphine oxide, thioxanthone compounds. A photoinitiator may be used independently and may use 2 or more types together. The content of the photopolymerization initiator is preferably 0.1 to 10 parts by weight, more preferably 0.5 to 5 parts by weight, per 100 parts by weight of the polymerizable liquid crystal compound.

Examples of dispersants include anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants. The content of the dispersant is preferably 0.05 to 10 parts by weight, more preferably 0.1 to 1 part by weight, per 100 parts by weight of the emulsion coating liquid.

Examples of leveling agents include acrylic leveling agents, fluorine-based leveling agents, and silicone-based leveling agents. The content of the leveling agent is preferably 0.05 to 10 parts by weight, more preferably 0.1 to 1 part by weight, per 100 parts by weight of the emulsion coating liquid.

Examples of cross-linking agents include aziridine-based cross-linking agents and isocyanate-based cross-linking agents. The content of the cross-linking agent is preferably 0.5 to 10 parts by weight, more preferably 0.8 to 5 parts by weight, per 100 parts by weight of the emulsion coating liquid.

The emulsion coating liquid includes, for example, a resin emulsion or resin particle dispersion containing polymer matrix-forming resin particles, a liquid crystal emulsion containing liquid crystal particles containing a liquid crystal compound and a polymerization initiator, and optional additives (e.g., dispersing agents, leveling agents, cross-linking agents). If desired, additional solvent may be added during mixing. Alternatively, the emulsion coating liquid can be prepared by adding a non-polymerizable liquid crystal compound, a polymerizable liquid crystal compound, a water-dispersible resin, a polymerization initiator and optional additives to a solvent and mechanically dispersing the liquid. obtain.

The above resin emulsion and liquid crystal emulsion can be prepared, for example, by mechanical emulsification, microchannel method, membrane emulsification, and the like. Among them, the liquid crystal emulsion is preferably prepared by the film emulsification method. According to the membrane emulsification method, an emulsion having a uniform particle size distribution can be suitably obtained. For details of the membrane emulsification method, reference can be made to disclosures such as JP-A-4-355719 and JP-A-2015-40994 (these are incorporated herein by reference).

The solid content concentration of the emulsion coating liquid can be, for example, 20% to 60% by weight, preferably 30% to 50% by weight.

The viscosity of the emulsion coating liquid can be appropriately adjusted so that the coating on the first transparent conductive film is preferably performed. The viscosity of the emulsion coating liquid at the time of application is preferably 20 mPas to 400 mPas, more preferably 30 mPas to 300 mPas, still more preferably 40 mPas to 200 mPas. If the viscosity is less than 20 mPas, the convection of the solvent becomes significant when the solvent is dried, and the thickness of the PDLC layer may become unstable. Also, if the viscosity exceeds 400 mPas, the bead of the emulsion coating liquid may not be stable. The viscosity of the emulsion coating liquid can be measured, for example, with a rheometer MCR302 manufactured by Anton Paar. The viscosity used here is the value of the shear viscosity under the conditions of 20° C. and a shear rate of 1000 (1/s).

The emulsion coating liquid is typically applied to the transparent electrode layer side surface of the first transparent conductive film. The first transparent conductive film is as described in Section A-1-1.

Any appropriate method can be adopted as the application method. Examples thereof include roll coating, spin coating, wire bar coating, dip coating, die coating, curtain coating, spray coating, and knife coating (comma coating, etc.). Among them, the roll coating method is preferable. For example, the description of Japanese Patent Application Laid-Open No. 2019-5698 can be referred to regarding coating by a roll coating method using a slot die.

The thickness of the coating layer is preferably 3 μm to 40 μm, more preferably 4 μm to 30 μm, still more preferably 5 μm to 20 μm. Within such a range, a PDLC layer with excellent thickness uniformity can be obtained.

B-2. Process B
In step B, the coating layer is dried to obtain a PDLC layer containing a polymer matrix and liquid crystal droplets containing a non-polymerizable liquid crystal compound and a polymerizable liquid crystal compound dispersed in the polymer matrix. The solvent is removed from the coating layer by drying, and the polymer matrix-forming resin particles are fused to each other to form a PDLC layer having a structure in which liquid crystal droplets are dispersed in the polymer matrix.

The drying of the coating layer can be performed by any appropriate method. Specific examples of the drying method include heat drying and hot air drying. When the emulsion coating liquid contains a cross-linking agent, a cross-linked structure of the polymer matrix may be formed during drying.

The drying temperature is preferably 20°C to 150°C, more preferably 25°C to 80°C. The drying time is preferably 1 minute to 100 minutes, more preferably 2 minutes to 10 minutes.

B-3. Process C
In step C, a second transparent conductive film is laminated on the PDLC layer. As a result, a PDLC film having the first transparent conductive film, the PDLC layer, and the second transparent conductive film in this order is obtained.

The second conductive film is as described in Section A-1-3, and the second transparent conductive film is laminated on the PDLC layer so that the second transparent electrode layer side faces the PDLC layer. It is done as follows. From the viewpoint of obtaining sufficient adhesion, the lamination is preferably performed using a laminator at a lamination pressure of 0.006 MPa / m to 7 MPa / m, more preferably 0.06 MPa / m to 0.7 MPa / m. can be done while applying

B-4. Process D
In step D, the PDLC layer is irradiated with an active energy ray in a predetermined pattern to form a first region containing liquid crystal droplets containing a liquid crystal polymer that is a polymerization product of a polymerizable liquid crystal compound and a non-polymerizable liquid crystal compound. Form. Specifically, in the region irradiated with the active energy ray (irradiated region), the polymerizable liquid crystal compound in the liquid crystal droplets is polymerized to form a liquid crystal polymer, resulting in the formation of a non-polymerizable liquid crystal compound and the liquid crystal polymer. A liquid crystal droplet containing is formed. On the other hand, in the area not irradiated with the active energy ray (non-irradiated area), the polymerizable liquid crystal compound remains unreacted, and as a result, the liquid crystal droplets contain the non-polymerizable liquid crystal compound and the polymerizable liquid crystal compound. Therefore, the irradiated region of the PDLC layer becomes the first region A containing the liquid crystal droplets containing the non-polymerizable liquid crystalline compound and the liquid crystal polymer, and the non-irradiated region contains the non-polymerizable liquid crystalline compound and the polymerizable liquid crystalline compound. becomes a second region B containing liquid crystal droplets containing The liquid crystal polymer contained in the liquid crystal droplets in the first region A is a polymerization product of the polymerizable liquid crystal compound contained in the liquid crystal droplets in the second region B. Note that the content ratio of the non-polymerizable liquid crystal compound and the polymerizable liquid crystal compound in the droplet in the non-irradiated region is the content ratio at the beginning of formation of the liquid crystal droplet, that is, the non-polymerizable liquid crystal compound in the coating liquid. It can roughly correspond to the content ratio with the polymerizable liquid crystal compound.

Irradiation of active energy rays is performed through a photomask with a predetermined pattern. As active energy rays, ultraviolet rays, infrared rays, X-rays, α-rays, β-rays, γ-rays, electron beams, and the like are used. Among them, ultraviolet rays are preferable. In addition, the active energy ray is preferably collimated light that travels straight from the irradiation source.

The ultraviolet irradiation conditions can be appropriately set according to the type of polymerizable liquid crystal compound, the transmittance of the transparent conductive film, the absorption wavelength of the photopolymerization initiator, and the like. The irradiation intensity can be, for example, 0.1 mW/cm ² to 1000 mW/cm ² , preferably 1 mW/cm ² to 100 mW/cm ² . The dose can be, for example, 10 mJ/cm ² to 10000 mJ/cm ² , preferably 100 mJ/cm ² to 5000 mJ/cm ² . The irradiation temperature can be, for example, -20°C to 80°C, preferably -20°C to 60°C.

FIGS. 3 and 4 are schematic diagrams each illustrating an example of active energy ray irradiation in the method for producing a PDLC film according to the embodiment of the present invention. In the embodiment shown in FIG. 3, active energy ray irradiation is performed through a photomask 40 in a state where no voltage is applied between the first transparent conductive film 10 and the second transparent conductive film 30. . According to the present embodiment, the polymerizable liquid crystal compound 24b is polymerized in the non-aligned state in the liquid crystal droplets 24 in the irradiated region of the PDLC layer 20, so the formed liquid crystal polymer 24c is also in the non-aligned state. Therefore, according to this embodiment, the PDLC film of the first embodiment described in Section A-1 can be obtained favorably.

In the embodiment shown in FIG. 4, the active energy ray irradiation is performed with a voltage applied between the first transparent conductive film 10 and the second transparent conductive film 30 through the photomask 40. . According to the present embodiment, in the liquid crystal droplets 24 in the irradiated region of the PDLC layer 20, the polymerizable liquid crystal compound 24b moves along the electric field in a predetermined direction (in the illustrated example, with respect to the main surfaces of the transparent conductive films 10 and 30). Since the polymerization is performed in the state of being oriented in the vertical direction), the liquid crystal polymer 24c in which the orientation is fixed is formed. Therefore, according to this embodiment, the PDLC film of the second embodiment described in Section A-2 can be obtained favorably. The voltage applied during the irradiation of the active energy ray is not limited as long as the desired orientation (in other words, the desired haze of the first region) is achieved, and is, for example, 10V to 200V, preferably 20V to 100V. could be.

In one embodiment, by performing active energy ray irradiation using a photomask having a plurality of light-transmitting portions with different aperture ratios, in a region corresponding to each light-transmitting portion, the second 1 region can be formed. Therefore, in the obtained PDLC film, the region corresponding to each light-transmitting portion can exhibit a haze corresponding to its aperture ratio in the overall view.

For example, by using a photomask in which the aperture ratio continuously increases from the right end to the left end, and performing active energy ray irradiation in a state in which no voltage is applied, the entire surface is in a scattering state when no voltage is applied, and no voltage is applied. A PDLC film can be obtained that exhibits an appearance in which the haze increases continuously from the right end to the left end upon application. Further, for example, by using a photomask in which the aperture ratio continuously increases from the right end to the left end, and performing active energy ray irradiation with a voltage applied, the entire surface is in a transparent state when the voltage is applied, and the voltage is applied. It is possible to obtain a PDLC film exhibiting an appearance in which the haze continuously decreases from the right end to the left end when no application is applied.

The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The measurement method of each characteristic is as follows. In addition, unless otherwise specified, "parts" and "%" in Examples and Comparative Examples are by weight.

(1) Thickness Measured using a digital micrometer (manufactured by Anritsu, product name “KC-351C”).
(2) Volume Average Particle Size of Liquid Crystal Particles in Liquid Crystal Emulsion 0.1% by weight of the liquid crystal emulsion was added to 200 ml of an aqueous electrolyte solution (manufactured by Coulter, "Isoton II"), and the resulting mixture was used as a measurement sample in a multisizer. 3 (manufactured by Coulter, aperture size = 20 μm), the volume average particle diameter was calculated by dividing the volume into 256 at equal intervals from 0.4 μm to 12 μm on a logarithmic basis and taking the statistics of the volume for each discretized particle diameter. . When particles of 12 μm or more are present, the aperture size is set to 30 μm, and the volume is divided into 256 at equal intervals from 0.6 μm to 18 μm on a logarithmic basis, and the volume of each discretized particle size is obtained. A volume average particle size was calculated.
(3) Average particle diameter of resin particles A measurement sample was prepared by adding several drops of a resin dispersion to 100 mL of water. Using a dynamic light scattering particle size distribution measuring device (manufactured by Microtrac, device name “Nanotrac150”), a measurement sample is set in the measurement holder of the device, and the concentration that can be measured is confirmed on the monitor of the device. Measurements were taken afterwards.
(4) Haze Measured according to JIS K 7136 using Nippon Denshoku's product name "NDH4000".

[Example 1]
(First and second transparent conductive films)
An ITO layer was formed on one surface of a PET substrate (thickness: 50 μm) by a sputtering method to obtain a transparent conductive film having a structure of [transparent substrate/transparent electrode layer].

(Preparation of emulsion coating liquid)
Non-polymerizable liquid crystal compound (manufactured by JNC, product name “LX-153XX”, birefringence Δn = 0.149 (ne = 1.651, no = 1.502), viscosity = 48.5 mPa s) 53.7 Part, polymerizable liquid crystal compound (manufactured by BASF, product name "PALIOCOLOR LC-242") 5.9 parts, photopolymerization initiator (manufactured by IGM, product name "OMNIRAD651") 0.1 part, pure water 39.8 and 0.5 part of a dispersing agent (“Noigen ET159” manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) were mixed and stirred at 100 rpm for 10 minutes with a homogenizer to prepare a liquid crystal emulsion. The average particle size of the liquid crystal particles in the resulting liquid crystal emulsion was 3.4 μm.
38.4 parts of the above liquid crystal emulsion, polyether-based polyurethane resin aqueous dispersion (manufactured by DSM, trade name "NeoRez R967", polymer average particle size: 80 nm, CV value = 0.27, solid content: 40 wt%)19. 1 part, polyester-based polyurethane resin aqueous dispersion (manufactured by Sanyo Kasei Co., Ltd., trade name "Ucoat C-102", polymer average particle size: 168 nm, CV value = 0.23, solid content: 45 wt%) 17.0 parts, 0.1 part of a leveling agent (manufactured by DIC, product name "F-444") and 1.1 part of a cross-linking agent (tris[3-(2-methylaziridin-1-yl)propionic acid]=propyridinetrimethyl) , and 24.3 parts of pure water were mixed to obtain an emulsion coating liquid (solid concentration: 40 wt %).

(Application and drying of emulsion coating liquid)
The above emulsion coating liquid was applied to the ITO layer surface of the first transparent conductive film to form a coating layer having a thickness of 20 μm. Coating was performed using a slot die and the line speed was 6 m/min. Then, the coating layer was dried at 25° C. for 8 minutes to form a PDLC layer having a thickness of 8 μm.

(Lamination of the second transparent conductive film)
While applying a lamination pressure of 0.4 MPa/m using a laminator, a second transparent conductive film was laminated on the PDLC layer such that the ITO layer faced the PDLC layer. A PDLC film was thus obtained.

(Active energy ray irradiation)
On both sides of the PDLC film, a part of the transparent conductive film was half-cut to the transparent base material to expose the transparent electrode layer, and the exposed part was used as an extraction electrode. A photomask having a predetermined pattern is placed on an electrode-treated PDLC film, and a voltage of 50 V is applied under a UV-LED lamp (manufactured by Hamamatsu Photonics, product name “C11924-101”, peak wavelength 365 nm). Exposure processing was performed at 10 mW/cm ² for 10 minutes.

[Example 2]
A PDLC film was obtained in the same manner as in Example 1, except that the ultraviolet irradiation was performed in a state in which no voltage was applied (applied voltage: 0 V).

The optical properties of the PDLC films obtained in Examples were evaluated by the following methods. Table 1 shows the results.
≪Optical properties≫
Using an AC power supply "EC750SA" manufactured by NF Circuit Design Block Co., Ltd., haze was measured when an AC voltage of 0 V to 50 V was applied to the PDLC film.

As shown in Table 1, in all of the PDLC films obtained in Examples, the amount of change in haze due to voltage application in the first region (irradiated region) was greater than that in the second region (unirradiated region). small. In addition, the PDLC film of Example 1 exhibits a predetermined pattern composed of a transparent first region and a cloudy second region when no voltage is applied. It exhibited a highly uniform appearance. On the other hand, the PDLC film of Example 2 exhibits a highly uniform appearance with a cloudy appearance on the entire main surface when no voltage is applied. It exhibited a predetermined pattern.

The PDLC film of the present invention is suitably used for various purposes such as advertisements, displays such as information boards, and smart windows.

100 PDLC film 10 first transparent conductive film 20 PDLC layer 22 polymer matrix 24 liquid crystal droplets 24a non-polymerizable liquid crystal compound 24b polymerizable liquid crystal compound 24c liquid crystal polymer 30 second transparent conductive film

Claims

a polymer-dispersed liquid crystal layer containing a polymer matrix and liquid crystal droplets dispersed in the polymer matrix; and a second transparent conductive film, in this order. A molecularly dispersed liquid crystal film,
The polymer-dispersed liquid crystal layer has a first region and a second region having different amounts of change in haze due to voltage application in plan view,
the amount of change in haze due to voltage application in the first region is smaller than the amount of change in the second region;
A polymer-dispersed liquid crystal film, wherein the liquid crystal droplets in the first region include a non-polymerizable liquid crystal compound and a liquid crystal polymer.
The polymer dispersed liquid crystal film according to claim 1, wherein the liquid crystal droplets in the second region contain a non-polymerizable liquid crystal compound and a polymerizable liquid crystal compound.
3. The content weight ratio of the non-polymerizable liquid crystal compound and the polymerizable liquid crystal compound (non-polymerizable liquid crystal compound:polymerizable liquid crystal compound) in the second region is 99:1 to 70:30. A polymer-dispersed liquid crystal film as described.
4. The polymer according to claim 2, wherein said liquid crystal polymer contained in said liquid crystal droplets in said first region is a polymerization product of said polymerizable liquid crystal compound contained in said liquid crystal droplets in said second region. Dispersion type liquid crystal film.
The polymer dispersed liquid crystal film according to any one of claims 1 to 4, wherein the difference between the haze of the first region and the haze of the second region is increased by voltage application.
The polymer dispersed liquid crystal film according to claim 5, wherein the liquid crystal polymer contained in the liquid crystal droplets in the first region is in a non-oriented state.
5. The polymer dispersed liquid crystal film according to any one of claims 1 to 4, wherein the difference between the haze of the first region and the haze of the second region is reduced by voltage application.
The polymer dispersed liquid crystal film according to claim 7, wherein the liquid crystal polymer contained in the liquid crystal droplets in the first region is oriented in a predetermined direction.
obtaining a coating layer by coating a first transparent conductive film with a coating liquid containing a polymer matrix-forming resin, a non-polymerizable liquid crystal compound, a polymerizable liquid crystal compound, and a solvent;
drying the coating layer to obtain a polymer-dispersed liquid crystal layer containing a polymer matrix and liquid crystal droplets containing the non-polymerizable liquid crystal compound dispersed in the polymer matrix and the polymerizable liquid crystal compound;
laminating a second transparent conductive film on the polymer-dispersed liquid crystal layer; and applying a voltage between the first transparent conductive film and the second transparent conductive film irradiating the polymer-dispersed liquid crystal layer with an active energy ray in a predetermined pattern to form a first liquid crystal droplet containing a liquid crystal polymer that is a polymerization product of the polymerizable liquid crystal compound and the non-polymerizable liquid crystal compound; forming a region;
A method for producing a polymer-dispersed liquid crystal film, comprising:
obtaining a coating layer by coating a first transparent conductive film with a coating liquid containing a polymer matrix-forming resin, a non-polymerizable liquid crystal compound, a polymerizable liquid crystal compound, and a solvent;
drying the coating layer to obtain a polymer-dispersed liquid crystal layer containing a polymer matrix and liquid crystal droplets containing the non-polymerizable liquid crystal compound dispersed in the polymer matrix and the polymerizable liquid crystal compound;
Laminating a second transparent conductive film on the polymer-dispersed liquid crystal layer, and without applying a voltage between the first transparent conductive film and the second transparent conductive film irradiating the polymer-dispersed liquid crystal layer with an active energy ray in a predetermined pattern to form a first liquid crystal droplet containing a liquid crystal polymer that is a polymerization product of the polymerizable liquid crystal compound and the non-polymerizable liquid crystal compound; forming a region;
A method for producing a polymer-dispersed liquid crystal film, comprising:
11. The polymer-dispersed liquid crystal according to claim 9, wherein the coating liquid is an emulsion coating liquid in which liquid crystal particles containing the non-polymerizable liquid crystal compound and the polymerizable liquid crystal compound are dispersed in the solvent. Film production method.
The weight ratio of the total content of the non-polymerizable liquid crystal compound and the polymerizable liquid crystal compound to the content of the polymer matrix-forming resin (liquid crystal compound: polymer matrix-forming resin) in the coating liquid is 12. The method for producing a polymer dispersed liquid crystal film according to any one of claims 9 to 11, wherein the ratio is 30:70 to 70:30.
10. From claim 9, wherein the content weight ratio of the non-polymerizable liquid crystal compound and the polymerizable liquid crystal compound (non-polymerizable liquid crystal compound:polymerizable liquid crystal compound) in the coating liquid is 99:1 to 70:30. 13. The method for producing a polymer dispersed liquid crystal film according to any one of 12.